The present invention relates to a filter unit and a video projector including the filter unit.
A video projector uses air current to cool optical system elements such as a light source lamp or a light valve. Such a video projector includes an air filter device that automatically cleans an air filter though which the air current flows. The video projector may be arranged facing any of various directions depending on where it is set. This may hinder maintenance of the air filter. Accordingly, an air filter device that is removable from a video projector and an air filter device that automatically cleans the air filter have been proposed.
Japanese Laid-Open Patent Publication No. 2008-65021 describes an air filter device including a pre-filter, a second filter, a third filter, and an elongated brush, which removes dust from the pre-filter. The elongated brush extends across a filtering surface of the pre-filter while holding opposite sides of the filtering surface. The pre-filter moves back and forth in a direction perpendicular to the longitudinal direction of the brush. As a result, the elongated brush removes dust from the pre-filter. The dust removed from the pre-filter is collected in a filter unit. The dust collected in the filter unit is disposed of by removing the filter unit from the air filter device.